Automatic sound signaling and regulating system for microphones used in electric alarm systems



June 30, 1931. J. P. WILLIAMS 1,812,616

AUTOMATIC SOUND SIGNALING AND REGULATING SYSTEM FOR MICROPHONES USED INELECTRIC ALARM SYSTEMS Filed Sept. 8, 1927 J44 Q n Patented June 30,1931 I umran starts PATENT OFFICE;

JofrIN P. WILLIAMS, F BAYSIDE, NEW YORK, ASSIGNOR TO DUPLEX ELECTRIGCOIM- PANY, OF NEW YORK, N. Y., A. CORPORATION OF DELAWARE AUTOMATICSOUN'D SIGNALING AND REGULATIN' SYSTEM FOR MICROPHONES USED IN ELECTRICALARM SYSTEMS Application filed September 8, 1927. Serial No. 218,351.

This invention relates to an automatic .sound regulating and signalingsystem for microphones used in electric alarm systems.

Electric burglar-alarm systems as now usually employed for theprotection of vaults or other structures comprise a. protective circuitconcealed within the protected structure and so arranged that an attackthereon will cause actuation of the circuit and i send a'signal or alarmto a distant station or desired point. An example of such .protec-' tivesystems is indicated. in my previous Patent No. 1, 56,926, of November28th, 1922.

7 It has become the custom to also employ 1151! in such protectivesystems microphone units concealed within the protected structure and soarranged in the protective circuit that an attack involving noise orsound will actuate the microphone and cause operation of the 2 signal oralarm circuit. One example of the supplementary use of microphones inelectric protective systems is indicated in my copending application forpatent, Serial No. 207,538, filed July 21, 1927.

The microphone units usually so employed are of the type which operateson the same general principles as a telephone transmitter, in which anysound will disturb the diaphragm and the vibration of the diaphragmdisarranges the normal position of small carbon balls resting againstits back, and this disarrangement or stirring-up of the carbon ballsmodifies resistance of the microphone and correspondingly modifies thecurrent passing therethrough. V

The difliculty experienced with such microphone protective systems hasbeen that unnecessary signals or alarms have been caused by operation ofthe microphones under the 40. action of local vibrations or outsidesound conditions (other than an actual attack by hammering, knocking orotherwise upon the protected structure), such as extraneous vi-'brations or sounds due to passing trolley cars, or trucks, near-byrailroad trains, thunder storms, lightning, etc. Y Y

It is the object of mypresent invention to entirely and effectivelyovercome; the disadvantages existing in such microphone protective'systems, and to provide an improved regulating system of this type whichwill afford full protection agains false signals or alarms due toordinary vibrations or sounds in the vicinity of the protected structureor to any inherent breaking or defect in the microphone unit itself.

To these ends'my improved system pro vides means intermediate of themicrophone units and the main signal or alarm which is located at thedistant station or desired point system for controlling the action ofthe microphone units to regulate or accumulate the vibrationspreliminary to any actuation of the main signal or alarm.

Referring to the drawings, the dotted outline 14 indicates the vault orother protected structure, within which the microphones and regulatingand controlling means and circuits thereof are protectively installed.The microphone units, indicated at 15 (I have herein shown two units inseries), are in circuit with the protective system of the vault orprotected structure, such protective circuit wires or conductorsbeingindicated at 16-17, and a battery or source of electrical energy,18, and a meter relay of usual construction, 19, are included in thecircuit. This circuit is completed through the microphones as follows:From the positive side of the battery18, through a wire, 20, to andthrough the coil, 21, of the relay 19, and from the coil through thewire 17 to the microphone 15 and across through a connecting wire, 22,to the other microphone 15, and fromthence back through the wire 16 tothe negative side of the battery 18. This continuous normallyclosedcircuit energizes the coil of the relay 19 and thus maintains thecontact needle,'28, of the relay in the normal position as shown.

The sound regulating means is preferably mounted or enclosed within asuitable boxing or casing, as indicated by the dotted outline 24, andthe mechanism is herein shown in a normally set position ready foroperation.

The preferred mechanismcomprises a suitable clock spring movementadapted to be key-wound, the gears, indicated at 25, of which controlthe operation of a hand or pointer, 26, fixed upon a revoluble shaft,27. Back of said pointer is mounted in fixed position a dial, 28,concentrically marked in steps to be indicated by the pointer.

I have herein shown the dial as marked in step points numbered 1 to 19running clockwise from a central point 0 at the top (which central pointis that at which the main signal or alarm will be actuated), but anyother suitable step-marking may be employed. The pointer is manually setas de sired with relation to the step points and the number ofmicrophone vibrations to be regulated oraccumulated to take up ordinaryextraneous sounds before the main signal or alarm is actuated. Forillustration, 1 have herein shown the pointer 26 set at the step figure5, which will afilord five vibration steps (4:, 3, 2, 1) in operationbefore the pointer reaches the main alarm pointrO. The step movement ofthe pointer is the reverse of clock-wise, moving from the higher to thelower step markings on the dial, and is controlled in its operationunder the suc cessive sound vibrations by the action of anelectro-magnet relay, 29, having its armature, 30,, carrying a. doggingspring, 31, to the end of which is pivotally mounted a ratchet pawl, 32,engaging one of the clock movement gears 25. the action being such thatthe operation of the armature 30 causes the ratchetipawl 32 to lock andrelease the clock movement and thus effect the travel of the pointer 26over the dial 28 in successive steps one point at a time.

Fixed to the pointer 26 and carried thereby, preferably back of thedial, is a disc, 33, of suitable insulating material, which disc carriestwo suitably spaced contact points, respectively indicated at 3 l85,both 01" which are grounded, as indicated at 36, to the positivepolarity of the main operating battery, shown 2115737. In the travel ofthe pointer these contact points respectively and successively makecontact with two spring contact plates, respectively indicated at 38-39, which are in circuit to indicate the travel of the pointer 26 andrespectively give a preliminary warning signal or alarm, and a finalmainsignal or alarm.

The arrangement and location of the contact points 3435 and the contactplates 3839 may be as desired with relation tothe step points on thedial and the travel of the pointer. In the present illustration, thespacing of the contact points 34-35 is such that when the pointer 26(set at the dial figure .5) moves to the dial figure 4; the springcontact plate 38 makes contact with the contact point 3-1 and completesa. circuit through a. Warning or preliminary signal which indicatesthatafter four more step movements of the pointer, caused by vibrations orsound waves, it will be at the main alarm point 0 at which a signal oralarm will be sent to the distant alarm station, and when the pointerreaches the alarm point 0 the spring contact plate 39 makes contact withthe contact point to complete the main alarm circuit.

It will be understood that the pointer 26 can be initially set at anydesired point with relation to the dial scale, according to the numberof vibration or sound steps it is desired to accumulate before thepreliminary warning signal or alarm is given, and that,

in the successive step movements thus provided forbefore the main signalor alarm is actuated, when the pointer reaches the dial figure l (in thepresent illustration of the relative location of the circuit contactpoints and the contact plates 3839) the preliminary alarm or signal willbe actuated.

T hen, if the step movements have been caused by extraneous or localvibrations 01' sounds other than an actual attack upon the protectedstructure, the pointer 26 can be again set back upon the dial scale tothe'desired point for further regulation of such extraneous vibrations;but, otherwise, if the vibrations or sounds continue or are caused byattack, the further step movements of the pointer will continue untilthe main alarm point 0 is,

reached, at which the main signal or alarm (which may be a gong, siren,lamp, or any other audible or visual device) at the main station will beactuated.

In the step-movement travel of the pointer and its disc the circuit ofthe preliminary warning signal or alarm will be broken as soon as thecontact point 34: passes the spring contact plate 38, and the circuit ofthe main signal or alarm will be set in operation as soon as the contactpoint 35 reaches the spring contact plate 39. V

' In operation, when the sound waves, caused by vibrations or an attackupon the protected structure, act upon the diaphragm of the microphones15, disturbing the position of the carbonballs in circuit and thuschanging the total resistance of the microphones, which resistancechange is of course due to the volume of the sound wave acting upon thediaphragm, the sudden change in resistance sets up a pulsating currenton the before described clos'ed circuit through the coil 21 of the meterrelay 19, and this pulsating current causes the contact needle 23 of therelay operating battery 37 through a wire, 41, to-

and through the contact needle 23 and contact point 40 and a wire, 42,to the coil, 43, of an automatic-drop relay, indicated at 44, andfromthence through a wire,'45, back to the negative side of the battery37.

The foregoing circuit energizes the coil of therelay 44 and attracts itsarmature,46, and the armature makes contact with a contact point, 47when another circuit co1nplete'd through the coil, 48, of the electro- Vmagnet 29 which controls the action of the sound regulating oraccumulating mecha nism, through conductors and meansias follows: Fromthe positive side of the operating battery 37, which is grounded,asindicated at 49, to the ground, indicated at 50, of the electro-magnetcoil- 48, through said coil 1 and a wire, 51, to the contact 47 andthrough the relay armature146 anda wire, 52, to the Wire 45, and fromthence to the negative side of the battery 37. 1

From the foregoing description it will'be noted that three circuitsarecomprised in the initial operation first, the initial normally closedprotective circuit; second,=an inter mediate circuit which is actuatedby the opening of the protective circuit; and third,.a supplementarycircuit which is actuated by the intermediate circuit and which in turncontrols the operation of the regulating mechanism which governs thesignaling or alarm circuits.

When the actuation of the supplementary circuit above describedenergizes the coil 48 of the electro-magnet 29, the armature 30 thereofis attracted and this releases the pawl ratchet 32, through the liftingof the dogging spring plate 31 carried by the armature, and theoperation of the clock-spring movement of the regulating mechanismstarts.

It will be understood that the foregoing action of the circuits andconsequent operation of the clock-spring movement is caused by a singlevibration or sound wave action upon the. microphones, and that when thissingle vibration ceases the microphones will resume theirnormally-closed circuit status through the carbon balls, the circuitsbefore described will resume normal status, and the clock-springmovement will be again locked upon release of the armature 30 of theelectro-magnet 29. By this action every single vibration of a givenvolume or sound causes the pointer 26 to move one step at a time overthe dial scale until the points are reached at which the preliminarywarning signal or alarm and then the main signal or alarm will berespectively actuated.

The. respective signal or alarm circuits, respectively including thespring contact plates 38 39, are completed through conductors and meansas follows: When the contact. plate 38 comes in contact with the initialcontact point 34 on the disc 33carried by the pointer 26, thewarning-signal circuit is completed from the ground 49 of the positiveside of the operating battery 37 to the ground 36 .of contact point 34,and from thence through said contact point and the contact plate 38 anda wire, 53, to and'through the warning signal or alarm, indicated at 54,(which may be a bell or other adapted means) and through a wire 55,backto the negative side of the battery 37. The completion of thiswarning signal circuit indicates that the pointer 26 is approachingwithin'a few step points of themain alarm point 0 and that in order toavoid theactuation of the main signal orfalarm unnecessarily byextraneous vibrations from any cause other than actual attack upon theprotected structure the pointer 26 should be moved back a desired numberof steps on the scale of the dial, andas soon as this is done the justdescribed warning circuit is of course broken.

But, under conditions of upon the protected structure, the consecutiveblows or hammering each cause a step movement of the pointer 26, and asthe blows con tinue the warning circuit is first actuated and as thepointer continues its movement the warning circuit is broken and themain signal or alarm circuit is completed, as soon as the alarm point 0is reached and the contact point 35 is in contact with the contact plate39, from the ground 49 of the positive side of the battery 37 to theground 36' ofcontact point 35, and from thence through said contact"point and the contact plate 39 and a wire, 56,

to and through the main signal or alarm, indicated at 57, and through awire, 58, and

the'wire 55 back to the negative side'of the battery 37 It will thus-benoted that there are two an actual attack operation the preliminarywarning signal cirj cuit is broken and there is no possibility of anycurrent passing through the wire 53 and V the warning signal 54. 1 1

It will also be noted that the before described intermediate circuitwhich 'is actuated by'the initial protective circuit and I whichactuates the automatic-drop relay 44, and the supplementarycircuit whichis -ac-,

tuated'b'ythe intermediate circuit and which actuates' theelectro-magnet 29 which operates J to release and lock the regulatingmeans, and also the two respective circuits from theregulating means andwhich respectively ac-r tuate the warning signal and the main signal,are. all operative on the mainoperating battery or source of electricalenergy 37, and that the initial protective circuit operates on its ownbattery 18.

It is also to be understood that the device operates equally as wellwith a'plurality of continuous alarms of intermittent duration as Wellas an alarm of continuous duration as the continuous sounds, and effectthe microphones the same as a plurality of intermittent alarms. Thedevice will thus operate either on the intermittent sound such ashammering, or on a sustained sound such as a Whistle or drilling.

The operation and advantages of my invention will be readily understood.By merely setting the pointer 26 at the desired point on the dial scaleany desired number of microphone vibrations can be regulatedoraccumulated before the warning signal or alarm is actuated, and when thewarning signal is given. the pointer can be again reset if desired, asthe numberof extraneous vibrations or sounds differs according to thelocality of the protected structure, and thus any unnecessary or falsealarms by actuation of the main signal or alarm will be conveniently andeffectively avoided, but the main signal or alarm will be actuated, inthe event of an attack upon the protected structure, as soon theregulated number of vibrations as provided for in the desired setting ofthe mechanism have beenaccumulated and the pointer reaches the alarmpoint 0 in its step movements. 1

I do not desire to be understood as limit.- ing myself to thedetailconstruction and arrangement of parts as herein shown anddescribed, as it is manifest that variations and modifications thereinmay be resorted to, in the adaptation of my invention to varyingconditions of use, without departing from the spirit and scope of myinvention and improvements. I therefore reserve the right to all suchvariations and modifications as properly fall within the scope of myinvention and the terms of the following claims.

Having thus described my invention, I

claim and desire ent I to secure by Letters Pat- 1. A microphoneprotective system of the class described for a structure to beprotected,

comp-rising a microphone sound detector located in a position to beactuated during a burglarious attack, a relay in circuit with saidmicrophone, movable means controlled by said relay responsive to bothintermittent and continuous vibrations of said sound detector, and analarm circuit controlled by said means to actuate said alarm only aftera predetermined movement of said means.

2. A microphone protective system of the class described for a structureto be protected comprising a microphone sound detector located in aposition to be actuated during a burglarious attack, a relay in circuitwith said microphone, a movable accumulator mechanism, an escapementmechanism controlled by said relay and moving said accumula'tormechanism, said escapement mechanism being moved in response to bothintermittent and continuous vibrations of said sound detector, and analarm circuit controlled by said accumulator mechanism to actuate saidalarm only after a predetermined movement of said accumulator mechanism,said accumulator mechanism being adapted to be reset a predeterminedamount.

8. A microphone protective system of the class described for a.structure to be protected, comprising a microphone sound detectorlocated in a position to be actuated duringa burglarious attack, a relayin circuit with said microphone and operated by the vibrations thereof,an escapement mechanism controlled by said relay responsive to bothintermittent and continuous vibrations of said sound detector, an alarmcircuit controlled by said escapement mechanism to actuate said alarmafter a. predetermined movement of said mechanism, a dial and a manuallycontrolled means to reset said escapement mechanism a predeterminedamount on said dial to determine the extent of movement thereof beforeactuation of said alarm.

In testimony whereof I have signed the foregoing specification.

JOHN P. WILLIAMS.

